Phun Physics... [Archive]

Pickers

23-11-2007, 19:54

I saw this done last year, and Clare reminded me about it by talking about freezing boiling water...
http://www.youtube.com/watch?v=fSPzMva9_CE
http://www.youtube.com/watch?v=EODql2ef6iQ
Basically, if pure water is chilled slowly to a low temperature (below freezing), there are no impurities to act as a nucleation centre for ice crystals to start growing. If the water is disturbed too much, then a nucleation point occurs and the whole mass of water will solidify in seconds, leading to much merriment.

I've yet to replicate the situation myself as the school freezer is too cluttered to leave the water undisturbed and I've yet to find a good brand to try it with.

Pheebs

23-11-2007, 19:58

NERD!

Hehehehehheheheheeehe!

Loving it though! Wanna do it! And then do some phun physics stuff ;) ;D

Goose

23-11-2007, 20:06

Very cool!

This reminds me of 'freezing rain', something most pilots of small aircraft dread to encounter. It has a great ability to kill engines, visibility and lift.

Pheebs

23-11-2007, 20:12

It has a great ability to kill engines, visibility and lift.

Like biffa women then?!

I just booked my place in hell :'(

Goose

23-11-2007, 20:15

I just booked my place in hell :'(
You'll have to do more than that to get a ticket!

SidewinderINC

23-11-2007, 21:51

That is pretty cool!

Would something similar work with pure ethanol? Say you chilled that to -20 or something, and then poured cold water in...

Actually, now I've written it down the water would just dilute the ethanol as -20 isn't cold enough to cause instant freezing of water.

Maybe if you chilled the ethanol down to -100 :p

goldilocks

23-11-2007, 22:01

i love physics (ionising radiation is where it's at ;))

but, isn't this more chemistry?
bond making, bond breaking, latent heat of fusion / evaporation, and all that?

Dr. Z

23-11-2007, 22:18

Non-newtonian fluid is similarly awesome:

http://www.metacafe.com/watch/348899/oobleck_a_non_newtonian_fluid/

SidewinderINC

23-11-2007, 22:21

i love physics (ionising radiation is where it's at ;))

but, isn't this more chemistry?
bond making, bond breaking, latent heat of fusion / evaporation, and all that?

Methinks so.

I never liked physics, I was good at it when it came down to it but at the time of choosing what to do I dropped that one.

divine

24-11-2007, 00:04

Physics was easier than Chemistry at A Level, so I took that one.

Pumpkinstew

24-11-2007, 00:50

They cut the footage right before he poured raspberry sauce all over is and made a slush puppy.

Pumpkinstew

24-11-2007, 00:54

But in A-level chemistry you do stuff like this:
http://www.youtube.com/watch?v=u6Ci4Lg47wQ

(and about 300 titrations)

SidewinderINC

24-11-2007, 01:26

titrations..... *groan*

lostkat

24-11-2007, 08:30

I hated Chemistry A-Level with a passion. All I can remember are learning about 900 different bloody benzene reactions and being told that the electron configurations (in the rings around the nucleus) you learn at GCSE are all LIIIIES!!!! Thought I'd escaped titrations when I finished my A-Levels. Had I thump. Had to do them at Uni too, booooo!!!

Pickers

24-11-2007, 09:24

i love physics (ionising radiation is where it's at ;))

but, isn't this more chemistry?
bond making, bond breaking, latent heat of fusion / evaporation, and all that?

Well latent heats/heat capacities are dealing with energy which is, by definition, an application of physics. That being said, material physics to some extent is part chemistry.

(Physics crosses into chemistry, and chemistry crosses into biology. There is no physics in biology hence constant jibbing between the disciplines ;))

Pheebs

24-11-2007, 10:05

You'll have to do more than that to get a ticket!

Like kill small innocent flies? ...... ;)

Does it matter if it's chemistry or pheesix?! They're both still NEEEEEEEERDy ;D

Hehehe I love this vid - I really wanna try it! I too think they made slush puppies out of them!

Could you imagine the sales you'd get on slush puppies if you sold it like that on the street! Everyone would want one and want a go at making their own!

goldilocks

24-11-2007, 10:09

i love my job! physics / anatomy and physiology - the perfect mix of sciences - just enough to keep me interested and learning, and not too much that i have to wear a lab coat and play with test tubes!!

omg - a level sciences were just wrong
i took maths (yes it is :P), physics, chemistry and human biology
i couldn't ditch physics quickly enough - only did AS
...and then realised i'd have to learn it all anyway for the degree
i'd love to take the a level exams again now - when it's actually and interest and not something i just *had* to learn

pickers, if you're a teacher - i think i'd have enjoyed the sciences a lot more if we'd have done experiment like that :)

Pumpkinstew

24-11-2007, 11:20

Physics crosses into chemistry, and chemistry crosses into biology. There is no physics in biology hence constant jibbing between the disciplines ;))

LIES! Lies I tell you!

Physics creeps into areas like limb mechanics and the physical strength of biological structures.

For example: WHAT is the air speed velocity of the east african swallow?:D

Having said that I have a friend who got his biology doctorate in insect flight and he's managed to publish papers without a single equation in them:huh:
There's physics in biology but they do their best to ignore it.;D

Pickers

24-11-2007, 11:37

The only physics I see in biology is pressure applied to the pencil nib in order to create different shades of red for colouring in the heart and lungs...
:p ;D ;D

Nah - biology is fun - I like teaching it (sometimes). I've learned so much about the human body recently that I'd either never known, or had forgotten since I last did it.

Oh - I did a heart dissection the other day and the kids wanted to film me "cos the other group's teacher had let them". "No way" says I, 'cos I've had no formal training and really don't want my inexperienced dissection (read: 'slice and tear until I stumble upon something interesting') plastered on you-tube. Of course I didnt say this to them - I said that it wasnt appropriate or respectful to the donor (pig).

Fayshun

24-11-2007, 13:36

For example: WHAT is the air speed velocity of the east african swallow?:D

Unladen? Or with coconuts?

kaiowas

13-12-2007, 23:57

I witnessed this effect first hand today. Came out of work to be greeted by a nice load of condensation on the inside of my windscreen which turned to ice as soon as I tried to wipe it off.

Will

14-12-2007, 00:33

Physics is the daddy of all sciences tbh. Without it the others would fail. I <3 physics - in fact I miss learning about it and doing it. More interested in metaphysics and astrophysics with a little does of quantum mechanics.

Von Smallhausen

14-12-2007, 14:09

That video was like watching Open University at 6am on BBC2 on a Sunday morning in the 80s. :)

Great stuff.

Pickers

14-12-2007, 18:15

I've decided to take my quantum leap DVDs in to school next week.. Phun Physics continues! :D

Von Smallhausen

14-12-2007, 18:43

I've decided to take my quantum leap DVDs in to school next week.. Phun Physics continues! :D

Make sure you take in the right DVDs. The school may not take too kindly to the Dutch version of Good Will Humping.

Pickers

02-10-2008, 18:03

Thread resurrection
In school today whilst sitting in the prep room I heard some rar rar music from a lab, and looked in on the Head of departments lesson on conservation of momentum. He had fired up you tube and was showing the year 13s this...
http://uk.youtube.com/watch?v=MlFlXMHaSVQ
(warning - lyrics on song maybe *NSFW*)

I have to say - I was lolling in the prep room. bizzare!

divine

02-10-2008, 18:14

CLICK CLICK BOOM

Belmit

02-10-2008, 20:18

:D

http://www.youtube.com/watch?v=xB7iz1HTh9U&NR=1

Desmo

02-10-2008, 21:02

Seen a couple of those gun clips before....didn't realise there were loads of them though :D

Del Lardo

02-10-2008, 21:46

Desmo

03-10-2008, 07:32

That refers to the size of the round....it's over half an inch in diameter :shocked:

Now whilst that doesn't always equate to a powerful round, it clearly is in this case ;D

Pickers

06-10-2008, 17:36

That refers to the size of the round....it's over half an inch in diameter :shocked:

Now whilst that doesn't always equate to a powerful round, it clearly is in this case ;D
In terms of conservation of momentum, with a large mass for the ballistic the recoil is gonna be quite sizable; even if the muzzle velocity is equal to or less than that of a smaller bullet.

Pickers

30-07-2010, 20:20

What Happens Next?

A balloon is fully inflated and attached to a valve. A semi inflated balloon is attached to the other end of the valve.

The valve is opened; what happens to the balloons?!

http://www.youtube.com/watch?v=7HO7JOrN4t4

Desmo

30-07-2010, 20:24

Without watching the video, I'd expect them to equalise in volume but I'm guessing I'm wrong :D

Lozza

30-07-2010, 20:49

Mark

30-07-2010, 21:34

I sense shenanigans! :)

I'd suggest talking too, but I'm a worse offender! :)

divine

30-07-2010, 21:37

Lozza

30-07-2010, 21:37

I sense shenanigans! :)

Those balloons don't look much like balloons :D

Mark

30-07-2010, 21:44

I'd guess it's something to do with why the first part of blowing up a balloon is the hardest bit, less strength/tension/whatever in the material so it gives far easier than the material on the less inflated one.

True - if the first balloon had previously been inflated, and the second one hadn't, that would help a lot.

Belmit

30-07-2010, 22:25

Whilst I haven't done Physics since A-level, my first thought was that if both balloons were identical shapes and thicknesses that the pressure would equalise and both balloons would stay at the same size with an equal amount of air in them. Thinking about it though, when you blow a balloon up it takes a huge amount of effort to start it, then gradually less and less after a certain point. When the air is released it comes out slowly at first then the last bit shoots out very quickly indeed. This suggests that up to a point the pressure is incredibly high in the small balloon, certainly greater then in the larger one. Hence the result.

Briggykins

30-07-2010, 22:36

I think the real question here is what's on your t-shirt?

Pickers

31-07-2010, 08:41

Well done Divine and Belmit. Whilst I dont know the actual relationship linking diameter to rubber tension, it is non linear. I think its similar to loading up an elastic band, initually its can take a couple of newtons before really extending, and then it "creeps" (get longer without actually applying any more force)

I dont do talking. I do it for my job. I become a mute over the holidays ;)

And Briggy, its a penguin mate :p